I. Field of the Invention
The present invention relates generally to a composition for a multivitamin/multimineral supplement and more specifically, to a composition useful as a prenatal iron supplement.
II. Description of the Prior Art
Iron is needed for the production of red blood cells and for a healthy circulatory system used to deliver nutrients and energy to muscles, organs, and other bodily tissue for maintaining a strong and healthy body. Particularly, iron occupies a central position in hemoglobin synthesis and erythropoiesis. An iron deficiency generally interferes with this process and, in time, often leads to anemia. The signs and symptoms of iron deficiency are generally attributable to the anemia it produces. Symptoms include weakness, fatigue, dizziness, heart palpitations, nausea, anorexia, constipation and menstrual irregularities. In the United States, it is estimated that about 2% of the men and more than about 15% of the women of child bearing age are deficient in iron. For example, a study estimated that about 38% of women of child bearing age in San Diego are iron deficient. It is therefore desirable to provide an iron supplement for reducing iron deficiency.
Blood loss is the most common cause of iron deficiency in adults. The high deficiency of iron in women is due to the obligatory blood loss of each menstrual cycle. Bleeding from the gastrointestinal tract (for example, because of peptic ulcer, diverticulosos, or malignancy) is the primary cause of iron deficiency in men. Impaired absorption of iron following total or partial gastrectomy and in patients with chronic diarrhea and/or malabsorption may also cause depletion of iron reserves. Increased demand for iron in infants, young children, adolescents, and adults may also lead to an iron-deficiency state. Lifestyle changes resulting from increased workloads, exercise, and/or routine physical activity for example, cause bodily changes generally leading to an increase in the demand for iron. For example, pregnancy generally increases the demands for iron in a woman's body. Particularly, during the second half of pregnancy, the demands for iron are significant. The increased demand for iron is frequently compounded by inadequate intake of iron because of an iron poor diet. It is therefore desirable to provide an iron supplement for addressing iron deficiency, anemia, and the increase in demands for iron.
Further related to pregnancy, a supplement of iron is important because many health problems with the mother and/or fetus may be associated with an inadequate amount of dietary iron. For example, anemia during pregnancy is associated with a significant increase in maternal mortality. Particularly, anemia in the third trimester can be dangerous if left untreated. Statistically, up to about 20% of all pregnant women suffer from anemia. Generally, as the pregnancy progresses, the demands for iron rise and, in many cases, these growing demands cannot be met by either the iron provided in a mother's normal diet or by her body's own iron reserves. Accordingly, iron supplementation is needed throughout the term of a pregnancy and for as long as a woman is lactating.
To address anemia as well as the increasing demands of iron, it has been recommended that a supplementation of iron be given to ensure that approximately 3 mg of iron is absorbed into the body per day. The prior art has provided supplementation of iron for the body through the use of caplets, tablets, soft/hard shell capsules, and suspensions including an iron salt. There are many iron salts included in supplements, such as ferric salts (Fe3+), ferrous salts (Fe2+) and carbonyl iron. Examples of ferrous iron salts include ferrous sulfate and ferrous fumarate
The use of iron salts, as with most metal salts, however, generally presents weaknesses and drawbacks. When supplements including commonly used ferric (Fe3+) salts (also referred to as iron (III) salts) are ingested and exposed to gastric juices having an acidic pH of between 1 and 3 in the stomach, the ferric iron (Fe3+) is converted to ferrous iron (Fe2+). It is this ferrous state of the iron that is most absorbed by the small intestine. However, conversion of the ferric iron (Fe3+) to the ferrous iron (Fe2+) form causes gastric upset and abdominal pain. In fact, a large percentage of patients that consume common iron salts complain of gastrointestinal tract upset. Further, such conversion results in a small, unsatisfactory percentage of the total iron in the supplement being absorbed. It would, therefore, be desirable to have a supplement wherein the iron is absorbed without an accompanying gastrointestinal upset and discomfort.
Further, organic or inorganic salt forms of iron are difficult to absorb in the human body and, therefore, are needed in large amounts to satisfy the daily iron requirements and the increase in iron demand. More specifically, following ingestion and ionization of an iron salt, such as ferrous sulfate (FeSO4), it is eventually transported to the small intestine where the majority of absorption takes place. Generally, absorption begins in the duodenum in a mildly acidic fluid environment (pH of about 5-6), and is maximal in the upper jejunum where the fluid is mildly basic (pH of about 7-8). The intestinal walls possess charges on the luminal surface that present a challenge for the passage or absorption of positively charged cationic metal species (Fe2+) to pass through the intestinal wall. These charges, however, allow the negatively charged anionic counter ion species (SO4−2) to pass through the intestinal membrane. Thus, most of the vital metal (positive cationic metal) is generally excreted from the body through the intestinal tract while the absorbed anions are cleared hepatically and exit the body in the urine. Such metabolic pathways are further discussed in Kirchoff, H. W. “The Treatment of Iron Deficiency Anemia with Iron Chelate Tablets”, Therapiewoche 33(37), 4833-4842, 1983, the disclosure of which is herein incorporated by reference in its entirety.
Efforts have been made to increase the absorption and decrease the clearance of iron by the body. More specifically, increasing the concentration of the iron in salt forms utilizing organic or inorganic carriers associated with the iron have produced only limited success and have drawbacks associated therewith. For example, ferrous sulfate is the most widely used form of iron supplementation, particularly for pregnant and lactating females, and for treating various forms of iron deficiency anemia, as described in Schuette, S., et al., “Comparison of Tolerability between Bisglycino-iron and Ferrous Sulfate in Normal Premenopausal Women”, Final Report to Albion Labs, University of Chicago, 1989, the disclosure of which is herein incorporated by reference in its entirety. However, while ferrous sulfate is absorbed into the blood stream and is widely prescribed, it too is sometimes not very well tolerated and produces abdominal discomfort and changes in bowel habits. This adversely affects treatment compliance in that patients frequently complain about gastric side effects such as diarrhea, constipation, abdominal pain, and nausea. Many times, this discomfort is the primary reason that a patient will stop taking a prescribed regimen. Thus, more tolerable forms of iron therapy would be desirable.
Further, patients may stop taking an iron-containing supplement as part of a prescribed regimen because the size of the supplement may be too large and, therefore, uncomfortable or difficult to swallow. Particularly, with respect to iron, due to the gastric conversion, low absorption, and high clearance rates of prior art forms of iron, large quantities of the iron need to be ingested in order to achieve the absorption of the recommended 3 mg of iron per day. In addition, the supplement itself may have a bad after taste. This is particularly true for expectant mothers, because upon becoming pregnant, the woman's sense of taste and smell and her ability to swallow certain foods changes. This often makes it difficult for a pregnant woman to maintain a regimen of ingesting prescribed supplements containing iron salts. Additionally, pregnant women generally consider a prenatal vitamin to be large and hard to swallow. For this reason, many women do not take prenatal vitamins according to the regimen their health care providers have prescribed or recommended.
As a result of the above drawbacks, many humans fail to take iron supplements as part of a required regimen. Consequently, iron levels often fall below those recommended, and the person may become anemic. Particularly, pregnant and lactating females failing to take prenatal vitamins as required may not get the nutrition that they and their developing fetus require. Consequently, many problems may arise with the pregnancy and/or with the child, up to and including mortality.
Thus, it would be desirable to provide a composition to supplement iron in a diet while avoiding deleterious side effects in the gastrointestinal tract. It would also be desirable to provide such a composition in a suitable dosage form, such as a tablet, containing iron in a form highly absorbed into the blood. It would be further desirable to reduce the size of the composition in order to facilitate adherence to a dosage regimen. To this end, it would be still further desirable that the regimen be satisfied by ingesting a single tablet once or only a few times per day. Compliance with a prenatal multivitamin/multimineral supplement is optimized with a once-a-day dosage. Finally, it would be desirable to accomplish the above while maintaining iron levels in pregnant females, particularly those suffering from anemia and/or in their third trimester, and lactating females at medically desirable levels.